I have a Bravia KDL-40W3000, which is almost 2 years old, & I've been able to use it as a full HD (1920x1080) monitor on my Dell Inspiron laptop via a VGA cable. It was tricky to get it set up, though, and the 1st VGA cable I tried did not have a full complement of pins and didn't work. Once I got it set up, every time I connect the laptop it defaults to the full HD resolution. Check which resolutions the video card in your HP can support.
i hook my hp laptop up to my sony bravia lcd tv all the time. you most likely need to right click your laptop home screen and click on resolution and you will see waht to do. you can tell it to show on both screens or just show on one. hope that helps